Scroll compressor

ABSTRACT

In a scroll compressor, by including a frame fixed at an internal space of a casing; a fixed scroll fixed to the frame and having an involute-shaped wrap; an orbiting scroll installed so as to perform an orbiting motion between the frame and the fixed scroll and having an involute-shaped wrap so as to form a compression space moving continually by being engaged with the wrap of the fixed scroll; a driving motor installed at the internal space of the casing in order to generate a driving force for making the orbiting scroll perform the orbiting motion; a discharge cover sealed-installed so as to form a discharge space with the fixed scroll; and an overheating preventive device including a temperature sensing device installed at the discharge cover so as to stop the operation of the driving motor when a temperature of a refrigerant gas is not less than a certain temperature and an over load protector installed at an upper portion of the driving motor, after sensing a temperature, by operating the over load protector directly, it is possible to cope with an overheating state of the compressor instantly, and accordingly it is possible to prevent damage of various parts due to overheating compression.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a scroll compressor, and in particular to a scroll compressor having an overheating preventive device capable of stopping operation of a driving motor electrically after sensing temperature of the discharge gas when a temperature of a discharge gas is not less than certain temperature.

[0003] 2. Description of the Prior Art

[0004] In general, a compressor is for converting mechanical energy into compression energy of a compressive fluid, and it is widely used for an air conditioner and a refrigerator, etc.

[0005] According to an operation type, the compressor can be divided into a reciprocating type, a vane type, a centrifugal type and a scroll type, etc.

[0006] The compressor consists of a compressing unit for compressing a fluid and a driving unit for operating the compressing unit, herein, a motor for converting electric energy into kinetic energy is commonly used as the driving unit.

[0007] Hereinafter, a scroll compressor having an overheating preventive device in accordance with the conventional art will be described in detail with reference to accompanying drawings.

[0008]FIG. 1 is a longitudinal-sectional view illustrating the conventional scroll compressor, FIG. 2 is an enlarged-sectional view illustrating a part A of FIG. 1, and FIG. 3 is a schematic view illustrating relation between a temperature sensor and an over load protector in accordance with the conventional art.

[0009] Unlike the reciprocating type using a linear motion of a piston, in the scroll type compressor using a rotational body as well as the centrifugal type or the vane type, by gearing plural scrolls and performing orbiting motions mutually, volume of a compression chamber is varied, and accordingly a refrigerant gas can be sucked, compressed and discharged.

[0010] As described above, the conventional scroll compressor includes a casing 1 having a suction pipe and a discharge pipe; a main frame 2 and a sub frame (not shown) fixed to both the top and bottom of the inner circumference of the casing 1; a driving motor 3 installed between the main frame 2 and the sub frame (not shown); a rotational shaft 4 pressed-inserted into the center of the driving motor 3 so as to penetrate the main frame 2 in order to transmit a rotational force of the driving motor 3; an orbiting scroll 5 combined with the rotational shaft 4 and arranged on the top surface of the main frame 2; a fixed scroll 6 combined with the orbiting scroll 5 and fixed to the top surface of the main frame 2 so as to form plural compression chambers; a valve assembly 7 combined with the rear of an end plate of the fixed scroll 6 in order to prevent a back-current of a discharge gas; and a discharge cover 8 combined with the rear of the fixed scroll 6 and partitioning the inside of the casing 1 into a suction pressure region and a discharge pressure region.

[0011] In the orbiting scroll 5 and the fixed scroll 6, plural wraps 5 a, 6 a forming plural compression chambers P by being engaged with each other are respectively formed as an involute shape. And, each top seal member 5 b, 6 b having an involute shape is inserted-combined with the front end of each wrap 5 a, 6 a so as to be movable up/down in order to prevent leakage of a compression gas toward the end plate.

[0012] In addition, on the end plate of the fixed scroll 6, a by-pass hole 6 c is formed so as to be connected with a suction side of the casing 1 in order to operate an OLP (over load protector) 9 arranged on the top of a stator 3A of the driving motor 3 by exhausting a discharge gas toward the suction side when a temperature of the discharge gas is not less than a certain temperature, as depicted in FIG. 2, a thermal switch 6 d using bimetal is installed on an inlet of the by-pass hole 6 c so as to be open when a temperature of the discharge gas is not less than a certain temperature.

[0013] In drawings, a non-explained reference numeral 3B is a rotor.

[0014] Hereinafter, the operation of the scroll compressor having the overheating preventive device in accordance with the conventional art will be described.

[0015] When power is supplied to the driving motor 3, the driving shaft 4 is rotated together with the driving motor 3, the orbiting scroll 5 orbits the rotating shaft 4 as an eccentric distance and forms plural compression chambers P with the wraps 5 a, 6 a of the fixed scroll 6, volume of the compression chamber P is decreased while moving toward the center by the continued orbiting motion of the orbiting scroll 5, the refrigerant gas is sucked, compressed and discharged, and the operation is performed repeatedly.

[0016]FIG. 3 is a schematic view illustrating relation between a temperature sensor and an over load protector in accordance with the conventional art. As depicted in FIG. 3, while repeating the sucking and compressing operation of the refrigerant gas, when a temperature of the refrigerant gas discharged into a discharge cover 8 rises above a certain temperature, by the operation of the thermal switch 6 d, the by-pass hole 6 c is open, and accordingly part of the refrigerant gas is leaked through the by-pass hole 6 c and is sucked into the inlet side of the casing 1. By the high temperature-refrigerant gas sucked into the inlet side, the over load protector 9 arranged on the top of the stator 3A is operated, power supplied to the driving motor 3 is cut off, and accordingly the operation of the compressor is stopped.

[0017] Hereinafter, problems of the overheating preventive device of the scroll compressor in accordance with the conventional art will be described.

[0018] As depicted in FIG. 3, in the conventional overheating preventive device of the scroll compressor, the operation of the compressor is stopped by operating the over load protector 9 by leaking part of the discharged refrigerant gas to the inlet side of the casing 1, so called an indirect control method is used. However, in that method, due to operation delay in each process such as an operation time of the thermal switch 6 d using bimetal, a time required for the high temperature-refrigerant gas to reach the over load protector 9 through the by-pass hole 6 c and an operation time of the over load protector 9 for sensing heat of the refrigerant gas and operating, etc., the total necessary time for preventing overheating of the compressor is increased, and accordingly parts such as the top seal member for sealing the wrap may be carbonized by the high temperature-compression gas.

SUMMARY OF THE INVENTION

[0019] In order to solve the above-mentioned problem, it is an object of the present invention to provide a scroll compressor having an overheating preventive device capable of preventing carbonization of various parts by sensing overheating of a compression gas in overheating occurrence and stopping operation of a compressor instantly.

[0020] In order to achieve the above-mentioned object, a scroll compressor in accordance with the present invention includes a frame fixed at an internal space of a casing; a fixed scroll fixed to the frame and having an involute-shaped wrap; an orbiting scroll installed so as to perform an orbiting motion between the frame and the fixed scroll and having an involute-shaped wrap so as to form a compression space moving continually by being engaged with the wrap of the fixed scroll; a driving motor installed at the internal space of the casing in order to generate a driving force for making the orbiting scroll perform the orbiting motion; a discharge cover sealed-installed so as to form a discharge space with the fixed scroll; and an overheating preventive device including a temperature sensing device installed at the discharge cover so as to stop the operation of the driving motor when a temperature of a refrigerant gas is not less than a certain temperature and an over load protector installed at an upper portion of the driving motor.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

[0022] In the drawings:

[0023]FIG. 1 is a longitudinal-sectional view illustrating part of the conventional scroll compressor;

[0024]FIG. 2 is an enlarged-detailed view illustrating part A of FIG. 1;

[0025]FIG. 3 is a schematic view illustrating relation between the conventional temperature sensor and an over load protector;

[0026]FIG. 4 is a longitudinal-sectional view illustrating an overheating preventive device of a scroll compressor in accordance with the present invention;

[0027]FIGS. 5 and 6 are longitudinal-sectional views illustrating modified examples of an overheating preventive device of a scroll compressor in accordance with the present invention;

[0028]FIG. 7 is a partial-sectional view illustrating a temperature sensor in accordance with the present invention;

[0029]FIG. 8A is a schematic view illustrating relation between the temperature sensor and the over load protector in accordance with the present invention in use of single phase power; and

[0030]FIG. 8B is a schematic view illustrating relation between the temperature sensor and the over load protector in accordance with the present invention in use of three phase power.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0031] Hereinafter, the preferred embodiment of a scroll compressor in accordance with the present invention will be described with reference to accompanying drawings.

[0032]FIG. 4 is a longitudinal-sectional view illustrating an overheating preventive device of a scroll compressor in accordance with the present invention, FIGS. 5 and 6 are longitudinal-sectional views illustrating modified examples of an overheating preventive device of a scroll compressor in accordance with the present invention, FIG. 7 is a partial-sectional view illustrating a temperature sensor in accordance with the present invention, FIG. 8A is a schematic view illustrating relation between the temperature sensor and the over load protector in accordance with the present invention in use of single phase power, and FIG. 8B is a schematic view illustrating relation between the temperature sensor and the over load protector in accordance with the present invention in use of three phase power.

[0033] As depicted in FIGS. 4˜8B, the scroll compressor includes a casing 10 having a suction pipe SP and a discharge pipe DP; a main frame 20 and a sub frame(not shown) fixed to both the top and bottom of the inner circumference of the casing 10; a driving motor 30 installed between the main frame 20 and the sub frame (not shown); a rotational shaft 40 pressed-inserted into the center of the driving motor 30 so as to penetrate the main frame 20 in order to transmit a rotational force of the driving motor 30; an orbiting scroll 50 combined with the rotational shaft 40 and arranged on the top surface of the main frame 20; a fixed scroll 60 combined with the orbiting scroll 50 and fixed to the top surface of the main frame 20 so as to form plural compression chambers; a valve assembly 70 combined with the rear of an end plate of the fixed scroll 60 in order to prevent a back-current of a discharge gas; a discharge cover 80 combined with the rear of the fixed scroll 60 and partitioning the inside of the casing 10 into a suction pressure region and a discharge pressure region; and an overheating preventive device consisting of a temperature sensor 105 as a temperature sensing device 100 installed at the discharge cover 80 in order to sense a temperature of a refrigerant gas discharged from the compression chamber P into the discharge cover 80 and an over load protector 90 installed at an upper portion of the driving motor 30 so as to be electrically connected to the temperature sensor 105 in order to cut off power of the driving motor when a temperature of the refrigerant gas is not less than a certain temperature.

[0034] In the orbiting scroll 50 and the fixed scroll 60, plural wraps 50 a, 60 a forming plural compression chambers P by being engaged with each other are respectively formed as an involute shape. And, each top seal member 50 b, 60 b having an involute shape is inserted-combined with the front end of each wrap 50 a, 60 a so as to be movable up/down in order to prevent leakage of a compression gas toward the end plate.

[0035] As depicted in FIG. 4, the discharge cover 80 is made of aluminum material having good heat conductivity, it is upwardly convex, the lower end thereof is fixed-combined with the rear of the end plate of the fixed scroll 60, a gas discharge pipe DP penetrating the casing 10 is connected to a side of the discharge cover 80, and the temperature sensor 100 is installed at the other side of the discharge cover 80.

[0036] In addition, the overheating preventive device consists of the temperature sensing device 100 installed at the discharge cover 80 in order to sense a temperature of a refrigerant gas discharged from the compression chamber P into the discharge cover 80; and the over load protector 90 installed at the upper portion of the driving motor 30 so as to be electrically connected to the temperature sensor 105 in order to cut off power of the driving motor when a temperature of the refrigerant gas is not less than a certain temperature.

[0037] As depicted in FIG. 4, in the temperature sensing device 100, a terminal insertion hole 125 is formed on the other side of the discharge cover 80 in which the gas discharge pipe DP is formed, and a sensor connection terminal 120 for connecting an output terminal 110 of the temperature sensor 105 is inserted-combined.

[0038] It is preferable to use a hermetic terminal which is generally welded-combined as the sensor connection terminal 120 so as to be sealed-inserted into the terminal insertion hole 125. In that case, the over load protector 90 is fixed-combined with the upper end of a stator 30A of the driving motor 30, herein, electrically direct-connection, in which current flows from an output side signal line 130 of the sensor connection terminal 120 of the temperature sensor 105 sensing an overheating of a refrigerant gas, is preferable.

[0039] As depicted in FIG. 5, in the temperature sensing device 100, a certain part of the temperature sensor 105 can be directly combined with the wall surface of the discharge cover 80.

[0040] In more detail, by forming a sensor insertion hole 126 at a certain side of the discharge cover 80, the temperature sensor 105 is inserted-combined with the sensor insertion hole 126 so as to be exposed a sensing portion of the temperature sensor 105 inwardly. In that case, it is possible to interpose an additional sealing material between the temperature sensor 105 and the sensor insertion hole 126, however, it is more preferable to seal them tightly by welding. In that case, the over load protector 90 is combined with the upper end of the stator 30A of the driving motor 30, and the over load protector 90 is electrically connected to the output terminal 110 of the temperature sensor 105 directly through the signal line 130.

[0041] In the meantime, as depicted in FIG. 6, it is possible to adhere-insert the temperature sensor 105 into the outer wall of the discharge cover 80 so as to sense a temperature of the refrigerant gas indirectly. In more detail, after forming a sensor insertion groove 127 at a certain side of the outer wall of the discharge cover 80 and inserting the sensing part of the temperature sensor 105 into the sensor insertion groove 127 so as to be tightly adhered to the outer wall of the discharge cover 80, and the sensor insertion groove 127 and the outer circumference of the temperature sensor 105 are combined with each other by welding.

[0042] In addition, the over load protector 90 is combined with the top end of the stator 30A of the driving motor 30, and the over load protector 90 is electrically connected to the output terminal 110 of the temperature sensor 105 through the signal line 130.

[0043] And, it is preferable to use a thermostat as the temperature sensor 105. As depicted in FIG. 7, the temperature sensor 105 includes a metal can 106 having a certain space, a bimetal 108 installed in the space of the metal can 106 for shutting/opening connection when a temperature of the refrigerant gas inside the space exceeds a preset temperature, and a base plate 107 installed around the outer circumference of the metal can 106 so as to support the bimetal 108.

[0044]FIGS. 8A and 8B are circuit diagrams illustrating relation between the temperature sensing device 100 and the over load protector 90 of the overheating preventive device in use of single phase power and three phase power.

[0045] As depicted in FIG. 8A, in use of single phase power, the temperature sensing device 100 is serially connected to a common line of a motor winding. Herein, the common line means a line not connected to a running capacity (CR).

[0046] As depicted in FIG. 8B, in use of three phase power, the temperature sensing device 100 is serially connected to the common line and one line or two lines of the motor winding. It is possible to use plural temperature sensing devices 100, and two temperature sensing devices are used in FIG. 8B.

[0047] Non-explained reference numeral 3B is a rotor, and 70 is a valve assembly.

[0048] The operation of the scroll compressor having the overheating preventive device in accordance with the present invention will be described.

[0049] When power is supplied to the driving motor 30, the driving shaft 40 is rotated together with the driving motor 30, the orbiting scroll 50 orbits the rotating shaft 40 as an eccentric distance and forms plural compression chambers P with the wraps 50 a, 60 a of the fixed scroll 60, volume of the compression chamber P is decreased while moving toward the center by the continued orbiting motion of the orbiting scroll 50, the refrigerant gas is sucked, compressed and discharged, and the operation is performed repeatedly.

[0050] Herein, the refrigerant gas is discharged from the compression chamber P to the discharge cover 80, is discharged again to a condenser of a refrigerant cycle apparatus through the gas discharge pipe DP, by installing the temperature sensor 105 at the inside of the discharge cover 80 as depicted in FIGS. 4 and 5 or arranging part of the temperature sensor 105 at the inside of the discharge cover 80 as depicted in FIG. 6, the temperature sensor 105 senses a present temperature of the refrigerant gas discharged to the discharge cover 80, compares the sensed temperature with a preset temperature value, when the sensed refrigerant gas temperature is higher than the preset temperature, by disconnecting the bimetal 108 inside the temperature sensor 105, current does not flow to the over load protector 90 installed at the upper end of the motor, and accordingly the operation of the motor is stopped. In more detail, in use of single phase power, by serially connecting the temperature sensing device 100, the common line of the motor winding and the over load protector 90 with each other, it is possible to stop the operation of the motor only with the temperature sensing device 100 although the over load protector 90 is out of order. And, in use of three phase power, it is possible to install plural temperature sensing devices 100, by serially connecting the temperature sensing device 100, the common line of the motor winding and the over load protector 90 with each other, it is possible to stop the operation of the motor only with the temperature sensing device 100 although the over load protector 90 is out of order.

[0051] Hereinafter, advantages of the scroll compressor and the overheating preventive device thereof in accordance with the present invention will be described.

[0052] In the scroll compressor, after sensing a temperature, by operating the over load protector directly, it is possible to cope with an overheating state of the compressor instantly, and accordingly it is possible to prevent damage of various parts due to overheating compression.

[0053] And, in use of single phase power or three phase power, by serially connecting the temperature sensing device 100, the common line of the motor winding and the over load protector 90 with each other, it is possible to stop the operation of the motor only with the temperature sensing device 100 although the over load protector 90 is out of order, and accordingly it is possible to cope with an overheating state of the compressor instantly and improve stability of the overheating preventive device. 

What is claimed is:
 1. A scroll compressor, comprising: a frame fixed at an internal space of a casing; a fixed scroll fixed to the frame and having an involute-shaped wrap; an orbiting scroll installed so as to perform an orbiting motion between the frame and the fixed scroll and having an involute-shaped wrap so as to form a compression space moving continually by being engaged with the wrap of the fixed scroll; a driving motor installed at the internal space of the casing in order to generate a driving force for making the orbiting scroll perform the orbiting motion; a discharge cover sealed-installed so as to form a discharge space with the fixed scroll; and an overheating preventive device including a temperature sensing device installed at the discharge cover so as to stop the operation of the driving motor when a temperature of a refrigerant gas is not less than a certain temperature and an over load protector installed at an upper portion of the driving motor.
 2. The scroll compressor of claim 1, wherein the temperature sensing device is serially connected to the over load protector and a common line of a motor winding which directly connects a power to the motor.
 3. The scroll compressor of claim 2, wherein power is single phase power.
 4. The scroll compressor of claim 2, wherein power is three phase power.
 5. The scroll compressor of claim 4, wherein there are two temperature sensing devices, and they respectively connect two electric lines of the common line of the motor winding to the over load protector serially.
 6. The scroll compressor of claim 3, wherein the temperature sensing device includes a temperature sensor which senses a temperature of a refrigerant gas and has an output terminal electrically connected to a signal line connected to the over load protector; and a sensor connection terminal which is electrically connected to the output terminal.
 7. The scroll compressor of claim 6, wherein the temperature sensor is formed as a metal can having a certain space and includes a bimetal and a base plate for supporting the bimetal.
 8. The scroll compressor of claim 7, wherein the sensor connection terminal is inserted-combined with a terminal insertion hole formed at the internal wall of the discharge cover in order to combine with an output terminal of the temperature sensor.
 9. The scroll compressor of claim 5, wherein the temperature sensing device includes a temperature sensor which senses a temperature of a refrigerant gas and has an output terminal electrically connected to a signal line connected to the over load protector; and a sensor connection terminal which is electrically connected to the output terminal.
 10. The scroll compressor of claim 9, wherein the temperature sensor is formed as a metal can having a certain space and includes a bimetal and a base plate for supporting the bimetal.
 11. The scroll compressor of claim 10, wherein the sensor connection terminal is inserted-combined with a terminal insertion hole formed at the internal wall of the discharge cover in order to combine with an output terminal of the temperature sensor.
 12. The scroll compressor of claim 3, wherein the temperature sensing device is a temperature sensor which senses a temperature of a refrigerant gas and has an output terminal electrically connected to a signal line connected to the over load protector.
 13. The scroll compressor of claim 12, wherein the temperature sensor is formed as a metal can having a certain space; and includes a bimetal and a base plate for supporting the bimetal.
 14. The scroll compressor of claim 13, wherein the temperature sensor is inserted-combined with a sensor insertion hole formed at the discharge cover.
 15. The scroll compressor of claim 14, wherein the temperature sensor is sealed-combined with the sensor insertion hole by welding.
 16. The scroll compressor of claim 5, wherein the temperature sensing device is a temperature sensor which senses a temperature of a refrigerant gas and has an output terminal electrically connected to a signal line connected to the over load protector.
 17. The scroll compressor of claim 16, wherein the temperature sensor is formed as a metal can having a certain space; and includes a bimetal and a base plate for supporting the bimetal.
 18. The scroll compressor of claim 17, wherein the temperature sensor is inserted-combined with a sensor insertion hole formed at the discharge cover.
 19. The scroll compressor of claim 13, wherein the temperature sensor is inserted-combined with the outer circumference of a sensor insertion groove curved-formed at the discharge cover in order to sense indirectly a temperature of a refrigerant gas transmitted to the discharge cover.
 20. The scroll compressor of claim 17, wherein the temperature sensor is inserted-combined with the outer circumference of a sensor insertion groove curved-formed at the discharge cover in order to sense indirectly a temperature of a refrigerant gas transmitted to the discharge cover. 